But-for Schedule Analysis is a forensic delay analysis method used in construction to determine the impact of specific delays on a project’s overall completion date.
The approach works by asking the question: but for the delay event, when would the project have finished? Analysts take the original schedule and remove the delay(s) under review, then recalculate the completion date to see how much earlier the project would have concluded.
This isolates the direct effect of the delay, separating it from other issues or concurrent events.
In practice, this method is often used in disputes to establish cause-and-effect between a delay event and the project’s late completion.
Use Cases for But-for Schedule Analysis
1- Dispute Resolution
But-for Analysis is widely used in construction claims and disputes to demonstrate how specific delays impacted project completion. By showing the hypothetical outcome if the delay had not occurred, it provides a strong evidentiary basis in arbitration or court proceedings.
2- Assessing Contractor Liability
Owners and consultants often use this method to evaluate whether a contractor is responsible for a project’s late delivery. It helps determine if the delay event was critical and directly attributable to the contractor’s actions or inactions.
3- Extension of Time (EOT) Claims
Contractors use But-for Analysis to justify requests for additional time. By removing employer-caused delays from the schedule, they can demonstrate that completion would have been achieved earlier without those delays, strengthening their entitlement to an EOT.
4- Insurance and Risk Assessment
In cases involving delay-related insurance claims, this method helps quantify the actual impact of disruptive events (e.g., extreme weather, labor strikes) on the project timeline, supporting fair compensation.
5- Forensic Project Review
Beyond disputes, project teams sometimes use But-for Analysis retrospectively to understand the root causes of delays and improve planning practices for future projects.
Pros & Cons
| Pros | Cons |
|---|---|
| Provides a clear cause-and-effect link between specific delays and project completion. | Relies heavily on the accuracy of the baseline schedule, which may be flawed or unrealistic. |
| Widely accepted in legal and arbitration proceedings due to its logical simplicity. | Can oversimplify complex projects with multiple overlapping or concurrent delays. |
| Useful for both owners and contractors in demonstrating entitlement or liability. | Often requires significant data manipulation, which may be disputed by opposing parties. |
| Creates a hypothetical “what-if” scenario that is easy to communicate to non-technical stakeholders. | May ignore real-world project dynamics, such as resequencing of work or mitigation measures. |
| Helps quantify time impacts in extension of time (EOT) and compensation claims. | Time-consuming to prepare and validate, especially for large-scale projects. |
How the But-for Method Works in Practice
The But-for Schedule Analysis starts with the project’s baseline or updated schedule, which serves as the reference point for evaluating progress and delays. The analyst identifies the delay event or events in question—such as late material delivery, design changes, or labor shortages—and then removes them from the schedule. By recalculating the completion date without those delays, the method reveals the hypothetical finish date that “would have” occurred if the delay had never happened.
This process creates a direct comparison between the actual completion date and the adjusted “but-for” completion date. The difference between the two represents the time impact of the delay. For example, if a project finished 60 days late but the analysis shows that without the employer-caused delays it would have been only 20 days late, then 40 days of delay can be attributed to the employer. This practical, step-by-step approach makes the But-for Method highly effective in isolating responsibility and providing a defensible explanation of delay impacts.
Common Challenges in Applying But-for Analysis
While the But-for Method is straightforward in theory, applying it in real projects often comes with challenges. One of the biggest issues is the reliability of the baseline or updated schedule used for the analysis. If the original schedule was unrealistic, incomplete, or poorly maintained, then the “what-if” scenario created by removing delays may not accurately reflect real project conditions. This can lead to disputes over the validity of the findings.
Another challenge lies in projects with multiple overlapping or concurrent delays. The But-for Method focuses on isolating the effect of a single delay, but construction projects often face several disruptions at the same time. In such cases, separating the true impact of each delay becomes complex and may oversimplify reality. Additionally, opposing parties in disputes often argue over how delays are modeled or whether mitigation efforts—like resequencing or accelerating work—were properly accounted for. These factors can make the method time-consuming and subject to debate, despite its apparent simplicity.
But For Schedule Analysis Example
Imagine a construction project with a planned duration of 12 months. Halfway through the project, the contractor experiences a 30-day delay due to late delivery of critical steel materials. The project ultimately finishes 60 days late.
To understand how much of that delay is attributable to the late steel delivery, a But-for Schedule Analysis is performed. The analyst takes the updated schedule and removes the steel delivery delay, then recalculates the completion date. The results show that, without this delay, the project would have been completed only 25 days late.
This means that out of the total 60 days of delay, 35 days can be directly attributed to the steel delivery issue. The remaining 25 days are due to other factors, such as slower-than-expected labor productivity or weather disruptions. By isolating responsibility in this way, the analysis provides a clear, evidence-based breakdown of delay causes.
Make But-for Schedule Analysis Faster and More Accurate with Opteam
When performing a But-for Schedule Analysis, accuracy and efficiency are crucial. Traditionally, gathering as-built data, comparing it to planned schedules, and isolating the “but-for” delays can take weeks of painstaking work. Opteam changes that.
With Opteam, consultants, contractors, and project managers can instantly import Primavera schedules, track real-time progress, and automatically identify deviations that matter. The platform highlights which delays truly impacted your project, so you can focus your analysis where it counts. Detailed reports and visual dashboards make presenting your findings to clients or stakeholders clear, concise, and defensible.
Whether you’re preparing a claim, assessing contractor performance, or conducting forensic schedule analysis, Opteam turns a complex, time-consuming process into a streamlined, data-driven workflow—saving you hours, improving accuracy, and helping you make better decisions faster.
